heel-toe downshifting is definately a good thing to learn when tracking. it is hard at first. but might i recommend you try it barefoot. thats how i learned to do it. it is pretty hard at first, i will admit, but once you get the hang of it, you'll be glad you did. i have pretty big feet, so the shoes i wear can get in the way alot, especially when i'm trying to do a little "spirited driving" on the backroads. though i wouldn't call it critical, especially since this is your first time auto-x'ing or tracking, it is definately essential if you want to pursue tracking more frequently in the future. i know stick shift driving bare-foot might seem odd, especially on the clutch foot, but if it makes it easier, leave one shoe on, and go barefoot (well a sock anyway) for your gas/brake pedal foot.
hth. another good thing for track runs, a friend with a camera. integras on tracks rule.